[PATCH RFC bpf-next 0/6] Add the the capability to load HW RX checsum in eBPF programs

[PATCH RFC bpf-next 0/6] Add the the capability to load HW RX checsum in eBPF programs

[Lorenzo Bianconi]

Introduce bpf_xdp_metadata_rx_checksum() kfunc in order to load the HW
RX cheksum results in the eBPF program binded to the NIC.
Implement xmo_rx_checksum callback for veth and ice drivers.

---
Lorenzo Bianconi (6):
      netlink: specs: Add XDP RX checksum capability to XDP metadata specs
      net: xdp: Add xmo_rx_checksum callback
      veth: Add xmo_rx_checksum callback to veth driver
      net: ice: Add xmo_rx_checksum callback
      selftests/bpf: Add selftest support for bpf_xdp_metadata_rx_checksum
      selftests/bpf: Add bpf_xdp_metadata_rx_checksum support to xdp_hw_metadat prog

 Documentation/netlink/specs/netdev.yaml            |  5 ++
 drivers/net/ethernet/intel/ice/ice_base.c          |  1 +
 drivers/net/ethernet/intel/ice/ice_txrx.h          |  1 +
 drivers/net/ethernet/intel/ice/ice_txrx_lib.c      | 82 ++++++++++++++++++++++
 drivers/net/veth.c                                 | 19 +++++
 include/net/xdp.h                                  |  6 ++
 net/core/xdp.c                                     | 29 ++++++++
 .../selftests/bpf/prog_tests/xdp_metadata.c        |  7 ++
 .../testing/selftests/bpf/progs/xdp_hw_metadata.c  |  7 ++
 tools/testing/selftests/bpf/progs/xdp_metadata.c   |  1 +
 tools/testing/selftests/bpf/xdp_hw_metadata.c      | 27 +++++++
 tools/testing/selftests/bpf/xdp_metadata.h         | 13 ++++
 12 files changed, 198 insertions(+)
---
base-commit: 315f423be0d1ebe720d8fd4fa6bed68586b13d34
change-id: 20250915-xdp-meta-rxcksum-963cb3a793e7

Best regards,
-- 
Lorenzo Bianconi <lorenzo@kernel.org>

[PATCH RFC bpf-next 1/6] netlink: specs: Add XDP RX checksum capability to XDP metadata specs

[Lorenzo Bianconi]

Introduce XDP RX checksum capability to XDP metadata specs. XDP RX
checksum will be use by devices capable of exposing receive checksum
result via bpf_xdp_metadata_rx_checksum().

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 Documentation/netlink/specs/netdev.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index e00d3fa1c152d7165e9485d6d383a2cc9cef7cfd..00699bf4a7fdb67c6b9ee3548098b0c933fd39a4 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -61,6 +61,11 @@ definitions:
         doc: |
           Device is capable of exposing receive packet VLAN tag via
           bpf_xdp_metadata_rx_vlan_tag().
+      -
+        name: checksum
+        doc: |
+          Device is capable of exposing receive checksum result via
+          bpf_xdp_metadata_rx_checksum().
   -
     type: flags
     name: xsk-flags

-- 
2.51.0

[PATCH RFC bpf-next 2/6] net: xdp: Add xmo_rx_checksum callback

[Lorenzo Bianconi]

Introduce xmo_rx_checksum netdev callback in order allow the eBPF
program bounded to the device to retrieve the RX checksum result computed
by the hw NIC.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 include/net/xdp.h |  6 ++++++
 net/core/xdp.c    | 29 +++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 6fd294fa6841d59c3d7dc4475e09e731996566b0..481b39976ac8c8d4db2de39055c72ba8d0d511c3 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -581,6 +581,10 @@ void xdp_attachment_setup(struct xdp_attachment_info *info,
 			   NETDEV_XDP_RX_METADATA_VLAN_TAG, \
 			   bpf_xdp_metadata_rx_vlan_tag, \
 			   xmo_rx_vlan_tag) \
+	XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_CHECKSUM, \
+			   NETDEV_XDP_RX_METADATA_CHECKSUM, \
+			   bpf_xdp_metadata_rx_checksum, \
+			   xmo_rx_checksum)
 
 enum xdp_rx_metadata {
 #define XDP_METADATA_KFUNC(name, _, __, ___) name,
@@ -644,6 +648,8 @@ struct xdp_metadata_ops {
 			       enum xdp_rss_hash_type *rss_type);
 	int	(*xmo_rx_vlan_tag)(const struct xdp_md *ctx, __be16 *vlan_proto,
 				   u16 *vlan_tci);
+	int	(*xmo_rx_checksum)(const struct xdp_md *ctx, u8 *ip_summed,
+				   u32 *cksum_meta);
 };
 
 #ifdef CONFIG_NET
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 9100e160113a9a1e2cb88e7602e85c5f36a9f3b9..3edab2d5e5c7c2013b1ef98c949a83655eb94349 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -961,6 +961,35 @@ __bpf_kfunc int bpf_xdp_metadata_rx_vlan_tag(const struct xdp_md *ctx,
 	return -EOPNOTSUPP;
 }
 
+/**
+ * bpf_xdp_metadata_rx_checksum - Read XDP frame RX checksum.
+ * @ctx: XDP context pointer.
+ * @ip_summed: Return value pointer indicating checksum result.
+ * @cksum_meta: Return value pointer indicating checksum result metadata.
+ *
+ * In case of success, ``ip_summed`` is set to the RX checksum result. Possible
+ * values are:
+ * ``CHECKSUM_NONE``
+ * ``CHECKSUM_UNNECESSARY``
+ * ``CHECKSUM_COMPLETE``
+ * ``CHECKSUM_PARTIAL``
+ *
+ * In case of success, ``cksum_meta`` contains the hw computed checksum value
+ * for ``CHECKSUM_COMPLETE`` or the ``csum_level`` for
+ * ``CHECKSUM_UNNECESSARY``. It is set to 0 for ``CHECKSUM_NONE`` and
+ * ``CHECKSUM_PARTIAL``.
+ *
+ * Return:
+ * * Returns 0 on success or ``-errno`` on error.
+ * * ``-EOPNOTSUPP`` : means device driver does not implement kfunc
+ * * ``-ENODATA``    : means no RX-timestamp available for this frame
+ */
+__bpf_kfunc int bpf_xdp_metadata_rx_checksum(const struct xdp_md *ctx,
+					     u8 *ip_summed, u32 *cksum_meta)
+{
+	return -EOPNOTSUPP;
+}
+
 __bpf_kfunc_end_defs();
 
 BTF_KFUNCS_START(xdp_metadata_kfunc_ids)

-- 
2.51.0

[PATCH RFC bpf-next 3/6] veth: Add xmo_rx_checksum callback to veth driver

[Lorenzo Bianconi]

Implement xmo_rx_checksum callback in veth driver to report RX checksum
result to the eBPF program bounded to the NIC.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/veth.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index a3046142cb8e2658a30041129f8d298e5e0a5822..2a762cb132fd9fd90376965c65c4fedcc28a26c8 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -1692,6 +1692,24 @@ static int veth_xdp_rx_vlan_tag(const struct xdp_md *ctx, __be16 *vlan_proto,
 	return err;
 }
 
+static int veth_xdp_rx_checksum(const struct xdp_md *ctx, u8 *ip_summed,
+				u32 *cksum_meta)
+{
+	const struct veth_xdp_buff *_ctx = (void *)ctx;
+	const struct sk_buff *skb = _ctx->skb;
+
+	if (!skb)
+		return -ENODATA;
+
+	/* For locally generated packets ip_summed is set to
+	 * CHECKSUM_PARTIAL.
+	 */
+	*ip_summed = skb->ip_summed;
+	*cksum_meta = 0;
+
+	return 0;
+}
+
 static const struct net_device_ops veth_netdev_ops = {
 	.ndo_init            = veth_dev_init,
 	.ndo_open            = veth_open,
@@ -1717,6 +1735,7 @@ static const struct xdp_metadata_ops veth_xdp_metadata_ops = {
 	.xmo_rx_timestamp		= veth_xdp_rx_timestamp,
 	.xmo_rx_hash			= veth_xdp_rx_hash,
 	.xmo_rx_vlan_tag		= veth_xdp_rx_vlan_tag,
+	.xmo_rx_checksum		= veth_xdp_rx_checksum,
 };
 
 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \

-- 
2.51.0

[PATCH RFC bpf-next 4/6] net: ice: Add xmo_rx_checksum callback

[Lorenzo Bianconi]

Implement xmo_rx_checksum callback in ice driver to report RX checksum
result to the eBPF program bounded to the NIC.

Tested-by: Jesper Dangaard Brouer <hawk@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/intel/ice/ice_base.c     |  1 +
 drivers/net/ethernet/intel/ice/ice_txrx.h     |  1 +
 drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 82 +++++++++++++++++++++++++++
 3 files changed, 84 insertions(+)

diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c
index c5da8e9cc0a0e5551b340e70628813999059bcfe..e8ec419bdc98cb1f01e3c088698b0c4c0f97748f 100644
--- a/drivers/net/ethernet/intel/ice/ice_base.c
+++ b/drivers/net/ethernet/intel/ice/ice_base.c
@@ -591,6 +591,7 @@ static int ice_vsi_cfg_rxq(struct ice_rx_ring *ring)
 		}
 	}
 
+	ring->pkt_ctx.rxq_flags = ring->flags;
 	xdp_init_buff(&ring->xdp, ice_get_frame_sz(ring), &ring->xdp_rxq);
 	ring->xdp.data = NULL;
 	ring->xdp_ext.pkt_ctx = &ring->pkt_ctx;
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.h b/drivers/net/ethernet/intel/ice/ice_txrx.h
index 2fd8e78178a271c15fc054ef553bd509b1c8f8f3..96a2bb79e5e95fa0b9c6287eb9769bdecf47dec1 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.h
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.h
@@ -260,6 +260,7 @@ enum ice_rx_dtype {
 struct ice_pkt_ctx {
 	u64 cached_phctime;
 	__be16 vlan_proto;
+	u8 rxq_flags;
 };
 
 struct ice_xdp_buff {
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
index 45cfaabc41cbeb9b119a0e95547e012e0df1e188..5327b0389ec1a3708a469fa9986a1e565b20ecf7 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
@@ -555,6 +555,87 @@ static int ice_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
 	return 0;
 }
 
+/**
+ * ice_xdp_rx_checksum - RX checksum XDP hint handler
+ * @ctx: XDP buff pointer
+ * @ip_summed: RX checksum result destination address
+ * @cksum_meta: XDP RX checksum metadata destination address
+ *
+ * Copy RX checksum result (if available) and its metadata to the
+ * destination address.
+ */
+static int ice_xdp_rx_checksum(const struct xdp_md *ctx, u8 *ip_summed,
+			       u32 *cksum_meta)
+{
+	const struct ice_xdp_buff *xdp_ext = (void *)ctx;
+	const union ice_32b_rx_flex_desc *rx_desc = xdp_ext->eop_desc;
+	u16 rx_status0, rx_status1, ptype = ice_get_ptype(rx_desc);
+	struct libeth_rx_pt decoded = libie_rx_pt_parse(ptype);
+	bool ipv4, ipv6;
+
+	if (!libeth_rx_pt_has_checksum(xdp_ext->xdp_buff.rxq->dev, decoded))
+		goto checksum_none;
+
+	rx_status0 = le16_to_cpu(rx_desc->wb.status_error0);
+	rx_status1 = le16_to_cpu(rx_desc->wb.status_error1);
+	if ((xdp_ext->pkt_ctx->rxq_flags & ICE_RX_FLAGS_RING_GCS) &&
+	    rx_desc->wb.rxdid == ICE_RXDID_FLEX_NIC &&
+	    (decoded.inner_prot == LIBETH_RX_PT_INNER_TCP ||
+	     decoded.inner_prot == LIBETH_RX_PT_INNER_UDP ||
+	     decoded.inner_prot == LIBETH_RX_PT_INNER_ICMP)) {
+		const struct ice_32b_rx_flex_desc_nic *desc;
+		u16 csum;
+
+		desc = (struct ice_32b_rx_flex_desc_nic *)rx_desc;
+		*ip_summed = CHECKSUM_COMPLETE;
+		csum = (__force u16)desc->raw_csum;
+		*cksum_meta = csum_unfold((__force __sum16)swab16(csum));
+		return 0;
+	}
+
+	/* check if HW has decoded the packet and checksum */
+	if (!(rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_L3L4P_S)))
+		goto checksum_none;
+
+	ipv4 = libeth_rx_pt_get_ip_ver(decoded) == LIBETH_RX_PT_OUTER_IPV4;
+	if (ipv4 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EIPE_S))))
+		goto checksum_none;
+
+	if (ipv4 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_IPE_S))))
+		goto checksum_none;
+
+	ipv6 = libeth_rx_pt_get_ip_ver(decoded) == LIBETH_RX_PT_OUTER_IPV6;
+	if (ipv6 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_IPV6EXADD_S))))
+		goto checksum_none;
+
+	/* check for L4 errors and handle packets that were not able to be
+	 * checksummed due to arrival speed
+	 */
+	if (rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_L4E_S))
+		goto checksum_none;
+
+	/* check for outer UDP checksum error in tunneled packets */
+	if ((rx_status1 & BIT(ICE_RX_FLEX_DESC_STATUS1_NAT_S)) &&
+	    (rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EUDPE_S)))
+		goto checksum_none;
+
+	/* If there is an outer header present that might contain a checksum
+	 * we need to bump the checksum level by 1 to reflect the fact that
+	 * we are indicating we validated the inner checksum.
+	 */
+	if (decoded.tunnel_type >= LIBETH_RX_PT_TUNNEL_IP_GRENAT)
+		*cksum_meta = 1;
+
+	*ip_summed = CHECKSUM_UNNECESSARY;
+	return 0;
+
+checksum_none:
+	*ip_summed = CHECKSUM_NONE;
+	*cksum_meta = 0;
+
+	return 0;
+}
+
 /**
  * ice_xdp_rx_vlan_tag - VLAN tag XDP hint handler
  * @ctx: XDP buff pointer
@@ -584,4 +665,5 @@ const struct xdp_metadata_ops ice_xdp_md_ops = {
 	.xmo_rx_timestamp		= ice_xdp_rx_hw_ts,
 	.xmo_rx_hash			= ice_xdp_rx_hash,
 	.xmo_rx_vlan_tag		= ice_xdp_rx_vlan_tag,
+	.xmo_rx_checksum		= ice_xdp_rx_checksum,
 };

-- 
2.51.0

[PATCH RFC bpf-next 5/6] selftests/bpf: Add selftest support for bpf_xdp_metadata_rx_checksum

[Lorenzo Bianconi]

Introduce support to xdp_metadata selftest for bpf_xdp_metadata_rx_checksum
kfunc.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 tools/testing/selftests/bpf/prog_tests/xdp_metadata.c | 7 +++++++
 tools/testing/selftests/bpf/progs/xdp_metadata.c      | 1 +
 tools/testing/selftests/bpf/xdp_metadata.h            | 9 +++++++++
 3 files changed, 17 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
index 19f92affc2daa23fdd869554e7a0475b86350a4f..650f87c2bac03841606ceef25eec718b5dcf766f 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
@@ -258,6 +258,7 @@ static void refill_rx(struct xsk *xsk, __u64 addr)
 
 static int verify_xsk_metadata(struct xsk *xsk, bool sent_from_af_xdp)
 {
+	__u8 ip_summed = sent_from_af_xdp ? CHECKSUM_NONE : CHECKSUM_PARTIAL;
 	const struct xdp_desc *rx_desc;
 	struct pollfd fds = {};
 	struct xdp_meta *meta;
@@ -310,6 +311,12 @@ static int verify_xsk_metadata(struct xsk *xsk, bool sent_from_af_xdp)
 	if (!ASSERT_NEQ(meta->rx_hash, 0, "rx_hash"))
 		return -1;
 
+	if (!ASSERT_EQ(meta->ip_summed, ip_summed, "rx_ip_summed"))
+		return -1;
+
+	if (!ASSERT_EQ(meta->cksum_meta, 0, "rx_cksum_meta"))
+		return -1;
+
 	if (!sent_from_af_xdp) {
 		if (!ASSERT_NEQ(meta->rx_hash_type & XDP_RSS_TYPE_L4, 0, "rx_hash_type"))
 			return -1;
diff --git a/tools/testing/selftests/bpf/progs/xdp_metadata.c b/tools/testing/selftests/bpf/progs/xdp_metadata.c
index 09bb8a038d528cf26c5b314cc927915ac2796bf0..ef6a5584a1876a3c47440f21dca927ec783469dc 100644
--- a/tools/testing/selftests/bpf/progs/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/progs/xdp_metadata.c
@@ -98,6 +98,7 @@ int rx(struct xdp_md *ctx)
 	bpf_xdp_metadata_rx_hash(ctx, &meta->rx_hash, &meta->rx_hash_type);
 	bpf_xdp_metadata_rx_vlan_tag(ctx, &meta->rx_vlan_proto,
 				     &meta->rx_vlan_tci);
+	bpf_xdp_metadata_rx_checksum(ctx, &meta->ip_summed, &meta->cksum_meta);
 
 	return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
 }
diff --git a/tools/testing/selftests/bpf/xdp_metadata.h b/tools/testing/selftests/bpf/xdp_metadata.h
index 87318ad1117a1d677af121f11778178532e2a562..f0ef17b328866206b1e63f7d751abeaa78e90932 100644
--- a/tools/testing/selftests/bpf/xdp_metadata.h
+++ b/tools/testing/selftests/bpf/xdp_metadata.h
@@ -30,6 +30,11 @@ enum xdp_meta_field {
 	XDP_META_FIELD_VLAN_TAG	= BIT(2),
 };
 
+#define CHECKSUM_NONE		0
+#define CHECKSUM_UNNECESSARY	1
+#define CHECKSUM_COMPLETE	2
+#define CHECKSUM_PARTIAL	3
+
 struct xdp_meta {
 	union {
 		__u64 rx_timestamp;
@@ -48,5 +53,9 @@ struct xdp_meta {
 		};
 		__s32 rx_vlan_tag_err;
 	};
+	struct {
+		__u8 ip_summed;
+		__u32 cksum_meta;
+	};
 	enum xdp_meta_field hint_valid;
 };

-- 
2.51.0

[PATCH RFC bpf-next 6/6] selftests/bpf: Add bpf_xdp_metadata_rx_checksum support to xdp_hw_metadat prog

[Lorenzo Bianconi]

Introduce the capability to dump HW rx checksum in xdp_hw_metadat
program via bpf_xdp_metadata_rx_checksum() kfunc.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 .../testing/selftests/bpf/progs/xdp_hw_metadata.c  |  7 ++++++
 tools/testing/selftests/bpf/xdp_hw_metadata.c      | 27 ++++++++++++++++++++++
 tools/testing/selftests/bpf/xdp_metadata.h         | 10 +++++---
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
index 330ece2eabdb454da2bb2cbd297d2b2dd6efddc0..dc62d572e3ac6e2ef173b330da515757ea543415 100644
--- a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
@@ -110,6 +110,13 @@ int rx(struct xdp_md *ctx)
 	else
 		meta->hint_valid |= XDP_META_FIELD_VLAN_TAG;
 
+	err = bpf_xdp_metadata_rx_checksum(ctx, &meta->ip_summed,
+					   &meta->cksum_meta);
+	if (err)
+		meta->rx_cksum_err = err;
+	else
+		meta->hint_valid |= XDP_META_FIELD_CHECKSUM;
+
 	__sync_add_and_fetch(&pkts_redir, 1);
 	return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
 }
diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
index 3d8de0d4c96a7afdf5f60b2fdff73c22b876ce54..5e38aa1b565735c2e55fcf2f7b9e672db1348233 100644
--- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
@@ -219,6 +219,28 @@ static void print_vlan_tci(__u16 tag)
 	printf("PCP=%u, DEI=%d, VID=0x%X\n", pcp, dei, vlan_id);
 }
 
+static void print_rx_cksum(__u8 ip_summed, __u32 cksum_meta)
+{
+	const char *cksum = "CHECKSUM_NONE";
+
+	switch (ip_summed) {
+	case CHECKSUM_UNNECESSARY:
+		cksum = "CHECKSUM_UNNECESSARY";
+		break;
+	case CHECKSUM_COMPLETE:
+		cksum = "CHECKSUM_COMPLETE";
+		break;
+	case CHECKSUM_PARTIAL:
+		cksum = "CHECKSUM_PARTIAL";
+		break;
+	case CHECKSUM_NONE:
+	default:
+		break;
+	}
+
+	printf("rx-cksum: %s, csum_meta=0x%x\n", cksum, cksum_meta);
+}
+
 static void verify_xdp_metadata(void *data, clockid_t clock_id)
 {
 	struct xdp_meta *meta;
@@ -254,6 +276,11 @@ static void verify_xdp_metadata(void *data, clockid_t clock_id)
 		printf("No rx_vlan_tci or rx_vlan_proto, err=%d\n",
 		       meta->rx_vlan_tag_err);
 	}
+
+	if (meta->hint_valid & XDP_META_FIELD_CHECKSUM)
+		print_rx_cksum(meta->ip_summed, meta->cksum_meta);
+	else
+		printf("No rx_chsum, err=%d\n", meta->rx_cksum_err);
 }
 
 static void verify_skb_metadata(int fd)
diff --git a/tools/testing/selftests/bpf/xdp_metadata.h b/tools/testing/selftests/bpf/xdp_metadata.h
index f0ef17b328866206b1e63f7d751abeaa78e90932..0fd5e7172fe891275b3b1eb69c51a93a60ae353e 100644
--- a/tools/testing/selftests/bpf/xdp_metadata.h
+++ b/tools/testing/selftests/bpf/xdp_metadata.h
@@ -28,6 +28,7 @@ enum xdp_meta_field {
 	XDP_META_FIELD_TS	= BIT(0),
 	XDP_META_FIELD_RSS	= BIT(1),
 	XDP_META_FIELD_VLAN_TAG	= BIT(2),
+	XDP_META_FIELD_CHECKSUM = BIT(3),
 };
 
 #define CHECKSUM_NONE		0
@@ -53,9 +54,12 @@ struct xdp_meta {
 		};
 		__s32 rx_vlan_tag_err;
 	};
-	struct {
-		__u8 ip_summed;
-		__u32 cksum_meta;
+	union {
+		struct {
+			__u8 ip_summed;
+			__u32 cksum_meta;
+		};
+		__s32 rx_cksum_err;
 	};
 	enum xdp_meta_field hint_valid;
 };

-- 
2.51.0

Re: [PATCH RFC bpf-next 4/6] net: ice: Add xmo_rx_checksum callback

[Maciej Fijalkowski]

On Sat, Sep 20, 2025 at 02:20:30PM +0200, Lorenzo Bianconi wrote:
> Implement xmo_rx_checksum callback in ice driver to report RX checksum
> result to the eBPF program bounded to the NIC.
> 
> Tested-by: Jesper Dangaard Brouer <hawk@kernel.org>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  drivers/net/ethernet/intel/ice/ice_base.c     |  1 +
>  drivers/net/ethernet/intel/ice/ice_txrx.h     |  1 +
>  drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 82 +++++++++++++++++++++++++++
>  3 files changed, 84 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c
> index c5da8e9cc0a0e5551b340e70628813999059bcfe..e8ec419bdc98cb1f01e3c088698b0c4c0f97748f 100644
> --- a/drivers/net/ethernet/intel/ice/ice_base.c
> +++ b/drivers/net/ethernet/intel/ice/ice_base.c
> @@ -591,6 +591,7 @@ static int ice_vsi_cfg_rxq(struct ice_rx_ring *ring)
>  		}
>  	}
>  
> +	ring->pkt_ctx.rxq_flags = ring->flags;
>  	xdp_init_buff(&ring->xdp, ice_get_frame_sz(ring), &ring->xdp_rxq);
>  	ring->xdp.data = NULL;
>  	ring->xdp_ext.pkt_ctx = &ring->pkt_ctx;
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.h b/drivers/net/ethernet/intel/ice/ice_txrx.h
> index 2fd8e78178a271c15fc054ef553bd509b1c8f8f3..96a2bb79e5e95fa0b9c6287eb9769bdecf47dec1 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx.h
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx.h
> @@ -260,6 +260,7 @@ enum ice_rx_dtype {
>  struct ice_pkt_ctx {
>  	u64 cached_phctime;
>  	__be16 vlan_proto;
> +	u8 rxq_flags;
>  };
>  
>  struct ice_xdp_buff {
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> index 45cfaabc41cbeb9b119a0e95547e012e0df1e188..5327b0389ec1a3708a469fa9986a1e565b20ecf7 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> @@ -555,6 +555,87 @@ static int ice_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
>  	return 0;
>  }
>  
> +/**
> + * ice_xdp_rx_checksum - RX checksum XDP hint handler
> + * @ctx: XDP buff pointer
> + * @ip_summed: RX checksum result destination address
> + * @cksum_meta: XDP RX checksum metadata destination address
> + *
> + * Copy RX checksum result (if available) and its metadata to the
> + * destination address.
> + */
> +static int ice_xdp_rx_checksum(const struct xdp_md *ctx, u8 *ip_summed,
> +			       u32 *cksum_meta)

Hi Lorenzo,

any chance we could have some common code used both here and in
ice_rx_csum() ?

> +{
> +	const struct ice_xdp_buff *xdp_ext = (void *)ctx;
> +	const union ice_32b_rx_flex_desc *rx_desc = xdp_ext->eop_desc;
> +	u16 rx_status0, rx_status1, ptype = ice_get_ptype(rx_desc);
> +	struct libeth_rx_pt decoded = libie_rx_pt_parse(ptype);
> +	bool ipv4, ipv6;
> +
> +	if (!libeth_rx_pt_has_checksum(xdp_ext->xdp_buff.rxq->dev, decoded))
> +		goto checksum_none;
> +
> +	rx_status0 = le16_to_cpu(rx_desc->wb.status_error0);
> +	rx_status1 = le16_to_cpu(rx_desc->wb.status_error1);
> +	if ((xdp_ext->pkt_ctx->rxq_flags & ICE_RX_FLAGS_RING_GCS) &&
> +	    rx_desc->wb.rxdid == ICE_RXDID_FLEX_NIC &&
> +	    (decoded.inner_prot == LIBETH_RX_PT_INNER_TCP ||
> +	     decoded.inner_prot == LIBETH_RX_PT_INNER_UDP ||
> +	     decoded.inner_prot == LIBETH_RX_PT_INNER_ICMP)) {
> +		const struct ice_32b_rx_flex_desc_nic *desc;
> +		u16 csum;
> +
> +		desc = (struct ice_32b_rx_flex_desc_nic *)rx_desc;
> +		*ip_summed = CHECKSUM_COMPLETE;
> +		csum = (__force u16)desc->raw_csum;
> +		*cksum_meta = csum_unfold((__force __sum16)swab16(csum));
> +		return 0;
> +	}
> +
> +	/* check if HW has decoded the packet and checksum */
> +	if (!(rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_L3L4P_S)))
> +		goto checksum_none;
> +
> +	ipv4 = libeth_rx_pt_get_ip_ver(decoded) == LIBETH_RX_PT_OUTER_IPV4;
> +	if (ipv4 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EIPE_S))))
> +		goto checksum_none;
> +
> +	if (ipv4 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_IPE_S))))
> +		goto checksum_none;
> +
> +	ipv6 = libeth_rx_pt_get_ip_ver(decoded) == LIBETH_RX_PT_OUTER_IPV6;
> +	if (ipv6 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_IPV6EXADD_S))))
> +		goto checksum_none;
> +
> +	/* check for L4 errors and handle packets that were not able to be
> +	 * checksummed due to arrival speed
> +	 */
> +	if (rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_L4E_S))
> +		goto checksum_none;
> +
> +	/* check for outer UDP checksum error in tunneled packets */
> +	if ((rx_status1 & BIT(ICE_RX_FLEX_DESC_STATUS1_NAT_S)) &&
> +	    (rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EUDPE_S)))
> +		goto checksum_none;
> +
> +	/* If there is an outer header present that might contain a checksum
> +	 * we need to bump the checksum level by 1 to reflect the fact that
> +	 * we are indicating we validated the inner checksum.
> +	 */
> +	if (decoded.tunnel_type >= LIBETH_RX_PT_TUNNEL_IP_GRENAT)
> +		*cksum_meta = 1;
> +
> +	*ip_summed = CHECKSUM_UNNECESSARY;
> +	return 0;
> +
> +checksum_none:
> +	*ip_summed = CHECKSUM_NONE;
> +	*cksum_meta = 0;
> +
> +	return 0;
> +}
> +
>  /**
>   * ice_xdp_rx_vlan_tag - VLAN tag XDP hint handler
>   * @ctx: XDP buff pointer
> @@ -584,4 +665,5 @@ const struct xdp_metadata_ops ice_xdp_md_ops = {
>  	.xmo_rx_timestamp		= ice_xdp_rx_hw_ts,
>  	.xmo_rx_hash			= ice_xdp_rx_hash,
>  	.xmo_rx_vlan_tag		= ice_xdp_rx_vlan_tag,
> +	.xmo_rx_checksum		= ice_xdp_rx_checksum,
>  };
> 
> -- 
> 2.51.0
> 
> 

Re: [PATCH RFC bpf-next 4/6] net: ice: Add xmo_rx_checksum callback

[Lorenzo Bianconi]

[-- Attachment #1: Type: text/plain, Size: 3367 bytes --]

[...]
> 
> Hi Lorenzo,
> 
> any chance we could have some common code used both here and in
> ice_rx_csum() ?

Hi Maciej,

ack, I will look into it.

Regards,
Lorenzo

> 
> > +{
> > +	const struct ice_xdp_buff *xdp_ext = (void *)ctx;
> > +	const union ice_32b_rx_flex_desc *rx_desc = xdp_ext->eop_desc;
> > +	u16 rx_status0, rx_status1, ptype = ice_get_ptype(rx_desc);
> > +	struct libeth_rx_pt decoded = libie_rx_pt_parse(ptype);
> > +	bool ipv4, ipv6;
> > +
> > +	if (!libeth_rx_pt_has_checksum(xdp_ext->xdp_buff.rxq->dev, decoded))
> > +		goto checksum_none;
> > +
> > +	rx_status0 = le16_to_cpu(rx_desc->wb.status_error0);
> > +	rx_status1 = le16_to_cpu(rx_desc->wb.status_error1);
> > +	if ((xdp_ext->pkt_ctx->rxq_flags & ICE_RX_FLAGS_RING_GCS) &&
> > +	    rx_desc->wb.rxdid == ICE_RXDID_FLEX_NIC &&
> > +	    (decoded.inner_prot == LIBETH_RX_PT_INNER_TCP ||
> > +	     decoded.inner_prot == LIBETH_RX_PT_INNER_UDP ||
> > +	     decoded.inner_prot == LIBETH_RX_PT_INNER_ICMP)) {
> > +		const struct ice_32b_rx_flex_desc_nic *desc;
> > +		u16 csum;
> > +
> > +		desc = (struct ice_32b_rx_flex_desc_nic *)rx_desc;
> > +		*ip_summed = CHECKSUM_COMPLETE;
> > +		csum = (__force u16)desc->raw_csum;
> > +		*cksum_meta = csum_unfold((__force __sum16)swab16(csum));
> > +		return 0;
> > +	}
> > +
> > +	/* check if HW has decoded the packet and checksum */
> > +	if (!(rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_L3L4P_S)))
> > +		goto checksum_none;
> > +
> > +	ipv4 = libeth_rx_pt_get_ip_ver(decoded) == LIBETH_RX_PT_OUTER_IPV4;
> > +	if (ipv4 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EIPE_S))))
> > +		goto checksum_none;
> > +
> > +	if (ipv4 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_IPE_S))))
> > +		goto checksum_none;
> > +
> > +	ipv6 = libeth_rx_pt_get_ip_ver(decoded) == LIBETH_RX_PT_OUTER_IPV6;
> > +	if (ipv6 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_IPV6EXADD_S))))
> > +		goto checksum_none;
> > +
> > +	/* check for L4 errors and handle packets that were not able to be
> > +	 * checksummed due to arrival speed
> > +	 */
> > +	if (rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_L4E_S))
> > +		goto checksum_none;
> > +
> > +	/* check for outer UDP checksum error in tunneled packets */
> > +	if ((rx_status1 & BIT(ICE_RX_FLEX_DESC_STATUS1_NAT_S)) &&
> > +	    (rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EUDPE_S)))
> > +		goto checksum_none;
> > +
> > +	/* If there is an outer header present that might contain a checksum
> > +	 * we need to bump the checksum level by 1 to reflect the fact that
> > +	 * we are indicating we validated the inner checksum.
> > +	 */
> > +	if (decoded.tunnel_type >= LIBETH_RX_PT_TUNNEL_IP_GRENAT)
> > +		*cksum_meta = 1;
> > +
> > +	*ip_summed = CHECKSUM_UNNECESSARY;
> > +	return 0;
> > +
> > +checksum_none:
> > +	*ip_summed = CHECKSUM_NONE;
> > +	*cksum_meta = 0;
> > +
> > +	return 0;
> > +}
> > +
> >  /**
> >   * ice_xdp_rx_vlan_tag - VLAN tag XDP hint handler
> >   * @ctx: XDP buff pointer
> > @@ -584,4 +665,5 @@ const struct xdp_metadata_ops ice_xdp_md_ops = {
> >  	.xmo_rx_timestamp		= ice_xdp_rx_hw_ts,
> >  	.xmo_rx_hash			= ice_xdp_rx_hash,
> >  	.xmo_rx_vlan_tag		= ice_xdp_rx_vlan_tag,
> > +	.xmo_rx_checksum		= ice_xdp_rx_checksum,
> >  };
> > 
> > -- 
> > 2.51.0
> > 
> > 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH RFC bpf-next 1/6] netlink: specs: Add XDP RX checksum capability to XDP metadata specs

[Stanislav Fomichev]

On 09/20, Lorenzo Bianconi wrote:
> Introduce XDP RX checksum capability to XDP metadata specs. XDP RX
> checksum will be use by devices capable of exposing receive checksum
> result via bpf_xdp_metadata_rx_checksum().
> 
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  Documentation/netlink/specs/netdev.yaml | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
> index e00d3fa1c152d7165e9485d6d383a2cc9cef7cfd..00699bf4a7fdb67c6b9ee3548098b0c933fd39a4 100644
> --- a/Documentation/netlink/specs/netdev.yaml
> +++ b/Documentation/netlink/specs/netdev.yaml
> @@ -61,6 +61,11 @@ definitions:
>          doc: |
>            Device is capable of exposing receive packet VLAN tag via
>            bpf_xdp_metadata_rx_vlan_tag().
> +      -
> +        name: checksum
> +        doc: |
> +          Device is capable of exposing receive checksum result via
> +          bpf_xdp_metadata_rx_checksum().
>    -
>      type: flags
>      name: xsk-flags

nit: let's fold it into patch 2? Will be easier to git blame the
feature..

Re: [PATCH RFC bpf-next 2/6] net: xdp: Add xmo_rx_checksum callback

[Stanislav Fomichev]

On 09/20, Lorenzo Bianconi wrote:
> Introduce xmo_rx_checksum netdev callback in order allow the eBPF
> program bounded to the device to retrieve the RX checksum result computed
> by the hw NIC.
> 
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  include/net/xdp.h |  6 ++++++
>  net/core/xdp.c    | 29 +++++++++++++++++++++++++++++
>  2 files changed, 35 insertions(+)
> 
> diff --git a/include/net/xdp.h b/include/net/xdp.h
> index 6fd294fa6841d59c3d7dc4475e09e731996566b0..481b39976ac8c8d4db2de39055c72ba8d0d511c3 100644
> --- a/include/net/xdp.h
> +++ b/include/net/xdp.h
> @@ -581,6 +581,10 @@ void xdp_attachment_setup(struct xdp_attachment_info *info,
>  			   NETDEV_XDP_RX_METADATA_VLAN_TAG, \
>  			   bpf_xdp_metadata_rx_vlan_tag, \
>  			   xmo_rx_vlan_tag) \
> +	XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_CHECKSUM, \
> +			   NETDEV_XDP_RX_METADATA_CHECKSUM, \
> +			   bpf_xdp_metadata_rx_checksum, \
> +			   xmo_rx_checksum)
>  
>  enum xdp_rx_metadata {
>  #define XDP_METADATA_KFUNC(name, _, __, ___) name,
> @@ -644,6 +648,8 @@ struct xdp_metadata_ops {
>  			       enum xdp_rss_hash_type *rss_type);
>  	int	(*xmo_rx_vlan_tag)(const struct xdp_md *ctx, __be16 *vlan_proto,
>  				   u16 *vlan_tci);
> +	int	(*xmo_rx_checksum)(const struct xdp_md *ctx, u8 *ip_summed,
> +				   u32 *cksum_meta);
>  };
>  
>  #ifdef CONFIG_NET
> diff --git a/net/core/xdp.c b/net/core/xdp.c
> index 9100e160113a9a1e2cb88e7602e85c5f36a9f3b9..3edab2d5e5c7c2013b1ef98c949a83655eb94349 100644
> --- a/net/core/xdp.c
> +++ b/net/core/xdp.c
> @@ -961,6 +961,35 @@ __bpf_kfunc int bpf_xdp_metadata_rx_vlan_tag(const struct xdp_md *ctx,
>  	return -EOPNOTSUPP;
>  }
>  
> +/**
> + * bpf_xdp_metadata_rx_checksum - Read XDP frame RX checksum.
> + * @ctx: XDP context pointer.
> + * @ip_summed: Return value pointer indicating checksum result.
> + * @cksum_meta: Return value pointer indicating checksum result metadata.
> + *
> + * In case of success, ``ip_summed`` is set to the RX checksum result. Possible
> + * values are:
> + * ``CHECKSUM_NONE``
> + * ``CHECKSUM_UNNECESSARY``
> + * ``CHECKSUM_COMPLETE``
> + * ``CHECKSUM_PARTIAL``

What do you think about adding new UAPI enum here? Similar to
xdp_rss_hash_type for the hash. The values can match the internal
CHECKSUM_XXX ones with (BUILD_BUG_ONs to enforce the relationship).
Will be a bit nicer api-wise to have an enum than an opaque u8.

Re: [PATCH RFC bpf-next 1/6] netlink: specs: Add XDP RX checksum capability to XDP metadata specs

[Lorenzo Bianconi]

[-- Attachment #1: Type: text/plain, Size: 1321 bytes --]

On Sep 22, Stanislav Fomichev wrote:
> On 09/20, Lorenzo Bianconi wrote:
> > Introduce XDP RX checksum capability to XDP metadata specs. XDP RX
> > checksum will be use by devices capable of exposing receive checksum
> > result via bpf_xdp_metadata_rx_checksum().
> > 
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> >  Documentation/netlink/specs/netdev.yaml | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
> > index e00d3fa1c152d7165e9485d6d383a2cc9cef7cfd..00699bf4a7fdb67c6b9ee3548098b0c933fd39a4 100644
> > --- a/Documentation/netlink/specs/netdev.yaml
> > +++ b/Documentation/netlink/specs/netdev.yaml
> > @@ -61,6 +61,11 @@ definitions:
> >          doc: |
> >            Device is capable of exposing receive packet VLAN tag via
> >            bpf_xdp_metadata_rx_vlan_tag().
> > +      -
> > +        name: checksum
> > +        doc: |
> > +          Device is capable of exposing receive checksum result via
> > +          bpf_xdp_metadata_rx_checksum().
> >    -
> >      type: flags
> >      name: xsk-flags
> 
> nit: let's fold it into patch 2? Will be easier to git blame the
> feature..

ack, I will do it posting a proper series.

Regards,
Lorenzo

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH RFC bpf-next 2/6] net: xdp: Add xmo_rx_checksum callback

[Lorenzo Bianconi]

[-- Attachment #1: Type: text/plain, Size: 2641 bytes --]

> On 09/20, Lorenzo Bianconi wrote:
> > Introduce xmo_rx_checksum netdev callback in order allow the eBPF
> > program bounded to the device to retrieve the RX checksum result computed
> > by the hw NIC.
> > 
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> >  include/net/xdp.h |  6 ++++++
> >  net/core/xdp.c    | 29 +++++++++++++++++++++++++++++
> >  2 files changed, 35 insertions(+)
> > 
> > diff --git a/include/net/xdp.h b/include/net/xdp.h
> > index 6fd294fa6841d59c3d7dc4475e09e731996566b0..481b39976ac8c8d4db2de39055c72ba8d0d511c3 100644
> > --- a/include/net/xdp.h
> > +++ b/include/net/xdp.h
> > @@ -581,6 +581,10 @@ void xdp_attachment_setup(struct xdp_attachment_info *info,
> >  			   NETDEV_XDP_RX_METADATA_VLAN_TAG, \
> >  			   bpf_xdp_metadata_rx_vlan_tag, \
> >  			   xmo_rx_vlan_tag) \
> > +	XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_CHECKSUM, \
> > +			   NETDEV_XDP_RX_METADATA_CHECKSUM, \
> > +			   bpf_xdp_metadata_rx_checksum, \
> > +			   xmo_rx_checksum)
> >  
> >  enum xdp_rx_metadata {
> >  #define XDP_METADATA_KFUNC(name, _, __, ___) name,
> > @@ -644,6 +648,8 @@ struct xdp_metadata_ops {
> >  			       enum xdp_rss_hash_type *rss_type);
> >  	int	(*xmo_rx_vlan_tag)(const struct xdp_md *ctx, __be16 *vlan_proto,
> >  				   u16 *vlan_tci);
> > +	int	(*xmo_rx_checksum)(const struct xdp_md *ctx, u8 *ip_summed,
> > +				   u32 *cksum_meta);
> >  };
> >  
> >  #ifdef CONFIG_NET
> > diff --git a/net/core/xdp.c b/net/core/xdp.c
> > index 9100e160113a9a1e2cb88e7602e85c5f36a9f3b9..3edab2d5e5c7c2013b1ef98c949a83655eb94349 100644
> > --- a/net/core/xdp.c
> > +++ b/net/core/xdp.c
> > @@ -961,6 +961,35 @@ __bpf_kfunc int bpf_xdp_metadata_rx_vlan_tag(const struct xdp_md *ctx,
> >  	return -EOPNOTSUPP;
> >  }
> >  
> > +/**
> > + * bpf_xdp_metadata_rx_checksum - Read XDP frame RX checksum.
> > + * @ctx: XDP context pointer.
> > + * @ip_summed: Return value pointer indicating checksum result.
> > + * @cksum_meta: Return value pointer indicating checksum result metadata.
> > + *
> > + * In case of success, ``ip_summed`` is set to the RX checksum result. Possible
> > + * values are:
> > + * ``CHECKSUM_NONE``
> > + * ``CHECKSUM_UNNECESSARY``
> > + * ``CHECKSUM_COMPLETE``
> > + * ``CHECKSUM_PARTIAL``
> 
> What do you think about adding new UAPI enum here? Similar to
> xdp_rss_hash_type for the hash. The values can match the internal
> CHECKSUM_XXX ones with (BUILD_BUG_ONs to enforce the relationship).
> Will be a bit nicer api-wise to have an enum than an opaque u8.

ack, fine. I will fix it v1.

Regards,
Lorenzo


[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]